CA2099351C - Preparation of shaped zirconia particles - Google Patents
Preparation of shaped zirconia particlesInfo
- Publication number
- CA2099351C CA2099351C CA002099351A CA2099351A CA2099351C CA 2099351 C CA2099351 C CA 2099351C CA 002099351 A CA002099351 A CA 002099351A CA 2099351 A CA2099351 A CA 2099351A CA 2099351 C CA2099351 C CA 2099351C
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- Prior art keywords
- zirconia
- accordance
- weight
- aqueous
- acid
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- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 title claims abstract description 132
- 239000002245 particle Substances 0.000 title claims abstract description 55
- 238000002360 preparation method Methods 0.000 title description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 27
- 239000000203 mixture Substances 0.000 claims abstract description 24
- 239000000843 powder Substances 0.000 claims abstract description 20
- 239000011260 aqueous acid Substances 0.000 claims abstract description 11
- 238000002156 mixing Methods 0.000 claims abstract description 11
- 238000007493 shaping process Methods 0.000 claims abstract description 7
- 238000010438 heat treatment Methods 0.000 claims abstract description 5
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims description 36
- 239000000243 solution Substances 0.000 claims description 30
- 238000000034 method Methods 0.000 claims description 27
- 239000011148 porous material Substances 0.000 claims description 24
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 11
- 239000002253 acid Substances 0.000 claims description 8
- 238000001035 drying Methods 0.000 claims description 5
- PTHCMJGKKRQCBF-UHFFFAOYSA-N Cellulose, microcrystalline Chemical compound OC1C(O)C(OC)OC(CO)C1OC1C(O)C(O)C(OC)C(CO)O1 PTHCMJGKKRQCBF-UHFFFAOYSA-N 0.000 claims description 4
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 4
- 239000011363 dried mixture Substances 0.000 claims description 4
- 238000001125 extrusion Methods 0.000 claims description 4
- 238000000227 grinding Methods 0.000 claims description 4
- 229910017604 nitric acid Inorganic materials 0.000 claims description 4
- XOOUIPVCVHRTMJ-UHFFFAOYSA-L zinc stearate Chemical compound [Zn+2].CCCCCCCCCCCCCCCCCC([O-])=O.CCCCCCCCCCCCCCCCCC([O-])=O XOOUIPVCVHRTMJ-UHFFFAOYSA-L 0.000 claims description 4
- 239000007864 aqueous solution Substances 0.000 claims description 3
- 238000007873 sieving Methods 0.000 claims description 3
- 235000011149 sulphuric acid Nutrition 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 2
- BDAGIHXWWSANSR-UHFFFAOYSA-N Formic acid Chemical compound OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 claims 2
- 238000001354 calcination Methods 0.000 claims 1
- XBDQKXXYIPTUBI-UHFFFAOYSA-N dimethylselenoniopropionate Natural products CCC(O)=O XBDQKXXYIPTUBI-UHFFFAOYSA-N 0.000 claims 1
- 235000019253 formic acid Nutrition 0.000 claims 1
- 239000003054 catalyst Substances 0.000 description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 239000006057 Non-nutritive feed additive Substances 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 150000001735 carboxylic acids Chemical class 0.000 description 2
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 2
- 229910052753 mercury Inorganic materials 0.000 description 2
- 239000008188 pellet Substances 0.000 description 2
- 238000004438 BET method Methods 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229920000168 Microcrystalline cellulose Polymers 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 235000010980 cellulose Nutrition 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000010410 dusting Methods 0.000 description 1
- 239000008240 homogeneous mixture Substances 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 230000001050 lubricating effect Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 235000019813 microcrystalline cellulose Nutrition 0.000 description 1
- 239000008108 microcrystalline cellulose Substances 0.000 description 1
- 229940016286 microcrystalline cellulose Drugs 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 150000007522 mineralic acids Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000012429 reaction media Substances 0.000 description 1
- 238000007655 standard test method Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- -1 tsblets Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
- B01J21/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
- B01J21/066—Zirconium or hafnium; Oxides or hydroxides thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/0009—Use of binding agents; Moulding; Pressing; Powdering; Granulating; Addition of materials ameliorating the mechanical properties of the product catalyst
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Materials Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Manufacturing & Machinery (AREA)
- Ceramic Engineering (AREA)
- Structural Engineering (AREA)
- Inorganic Chemistry (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
- Catalysts (AREA)
- Compositions Of Oxide Ceramics (AREA)
- Glanulating (AREA)
Abstract
Shaped zirconia particles are prepared by mixing zirconia powder with an aqueous colloidal zirconia solution or an aqueous acid solution so as to obtain a shapable mixture containing about 4-40 weight-% water, shaping this mixture, and heating the shaped particles at a temperature in excess of about 90°C.
Description
~1~99351 PREPARATION OF SHAPED ZIRCONIA PARTICLES
Back~round of the Invention This invention relates to the preparation of shaped zirconia particles having high strength and high surface area.
Shaped zirconia particles (e.g., tsblets, pellets or extrudates) can be used as support materials in the preparation of various catalysts, such as CO oxidation catalysts (disc]osed in U.S.
Patent 4,921,830). A requirement for the successful commercial use of such catalysts in fixed bed operations is high crush strength (so as to assure the integrity of catalyst particles, especia]ly those at the bottom of catalyst beds, and to avoid undesirable dusting) and high surface area (so as to assure adequate exposure of the catalytically active components to the reaction medium). Since the ca-talytically active components are generally incorporated into the zirconia support particles by impregnation, it is frequently also important to provide shaped zirconia particles having adequate porosity. The prepflration process of this invention is designed to produce shaped zirconia particles meeting the above-outlined requirements. ~
Back~round of the Invention This invention relates to the preparation of shaped zirconia particles having high strength and high surface area.
Shaped zirconia particles (e.g., tsblets, pellets or extrudates) can be used as support materials in the preparation of various catalysts, such as CO oxidation catalysts (disc]osed in U.S.
Patent 4,921,830). A requirement for the successful commercial use of such catalysts in fixed bed operations is high crush strength (so as to assure the integrity of catalyst particles, especia]ly those at the bottom of catalyst beds, and to avoid undesirable dusting) and high surface area (so as to assure adequate exposure of the catalytically active components to the reaction medium). Since the ca-talytically active components are generally incorporated into the zirconia support particles by impregnation, it is frequently also important to provide shaped zirconia particles having adequate porosity. The prepflration process of this invention is designed to produce shaped zirconia particles meeting the above-outlined requirements. ~
2 ~09~351 -Summary of the Invention It is an object of this invention to prepare shaped zirconia particles having high crush strength and high surface area.
In accordance with this invention, a process for preparing shaped zirconia particles comprises the steps of (a) mixing zirconia powder with an aqueous colloidal solution of zirconia or, alternatively, an aqueous acid solution, and adjusting the water content of the obtained mixture to a level of about 5 to about 40 weight-% H20; (b) shaping the mixture obtained in step (a); and (c) heating the shaped particles obtained in step (b) at a temperature in excess of about 90C
(preferably about 300-750C).
Preferably, the zirconia powder employed in step (a) has a pore volume of about 0.2-0.5 cc/g (measured by water intrusion at atmospheric pressure), a surface area of about 20-150 ma/g (measured by the BET method using N2), and a particle size of about 0.1-5 microns.
Step (a) is preferably carried out as a sequence of five substeps: (al) rnixing zirconia powder with an aqueous colloidal solution of zirconia or, alternatively, an aqueous acid solution (more preferably dissolved H2S04 or CH3C02ll); ~a2) substantially drying the mixture obtained in step (al); (a3) grinding the substantially dried mixture obtained in (a2); (a4) selecting that portion of substantially dried particles having a particle size of about 20-325 mesh; and (aS) adding enough water to obtain a mixture containing about 8-30 weight-% H20. In a preferred embodiment, a lubricating processing aid (more preferably zinc stearate or cellulose gel) is also added in step (a5), either together with water or after the water addition or before the water addition.
In accordance with this invention, a process for preparing shaped zirconia particles comprises the steps of (a) mixing zirconia powder with an aqueous colloidal solution of zirconia or, alternatively, an aqueous acid solution, and adjusting the water content of the obtained mixture to a level of about 5 to about 40 weight-% H20; (b) shaping the mixture obtained in step (a); and (c) heating the shaped particles obtained in step (b) at a temperature in excess of about 90C
(preferably about 300-750C).
Preferably, the zirconia powder employed in step (a) has a pore volume of about 0.2-0.5 cc/g (measured by water intrusion at atmospheric pressure), a surface area of about 20-150 ma/g (measured by the BET method using N2), and a particle size of about 0.1-5 microns.
Step (a) is preferably carried out as a sequence of five substeps: (al) rnixing zirconia powder with an aqueous colloidal solution of zirconia or, alternatively, an aqueous acid solution (more preferably dissolved H2S04 or CH3C02ll); ~a2) substantially drying the mixture obtained in step (al); (a3) grinding the substantially dried mixture obtained in (a2); (a4) selecting that portion of substantially dried particles having a particle size of about 20-325 mesh; and (aS) adding enough water to obtain a mixture containing about 8-30 weight-% H20. In a preferred embodiment, a lubricating processing aid (more preferably zinc stearate or cellulose gel) is also added in step (a5), either together with water or after the water addition or before the water addition.
3 209~51 The presently preferred shaping means in step (c) is tabletting or extrusion.
Detailed Description of the Invention Zirconia powders which can be used in step (a) of the process of this invention are commercially available (e.g., from Zirconia Sales of America, Atlanta, GA). Preferably, the zirconia powder used in step (a) has a particle size of about 0.1-5 microns (more preferably about 0.5-1.2 microns), a pore volume (measured by water intrusion at atmospheric pressure) of about 0.2-0.5 cc/g (more preferably about 0.25-0.35 cc/g), and a BET/N2 surface area of about 25-150 m2/g (more preferably about 80-100 m2/g).
In step (a), the zirconia powder is mixed with either an aqueous colloidal solution of zirconia, preferably containing about 10-30 weight-70 of colloidal zirconia particles having a particle size of about 5-1000 (preferably about 5-200) nanometers, or alternatively, an aqueous mineral or carboxylic acid solution. Aqueous colloidal zirconia solutions are generally stabilized with acetic acid (preferred) or nitric acid and are commercially available (e.g., from PQ Corporation, Ashland, MA, under the product designation of Nyacol~). Non-limiting examples of suitable acids are H2S04, HN03, HCl, HC03H, CH3C02H, C2H5C02H, and higher carboxylic acids containing one or two carboxyl groups per molecule. Presently preferred are aqueous solution containing H2S04 or acetic acid, at a concentration of about 0.1 to 1.5 mol/l of the acid. Generally, the weight ratio of the colloidal zirconia solution or, alternatively, the aqueous acid solution to the zirconia powder is in the range of about 0.4:1 to about 1.5:1. Step (a) can be carried out in any suitable mixing device for a time period _ 4 2099351 sufficient to provide a substantially homogeneous mixture, generally for at least 1 minute (preferably about 5-20 minutes).
Step (a) is carried out so as to provide a shapable mixture containing about 5-40 (preferably about 8-30, more preferably about 8-15) weight-% H20. It is within the scope of this invention to carry out step (a) essentially in one step by adding enough water (either as part of the colloidal solutisn of zirconia or the aqueous acid solution, or in addition to these solutions) to provide the required water content. However, it is preferred to carry out step (a) as a series of substeps: (al) mixing powdered zirconia with an aqueous colloidal solution of zirconia or, alternatively, an aqueous solution of acetic or sulfuric acid, as described above; (a2) substantially drying the obtained wet mixture (preferably at a temperature of about 60-120C);
(a3) grinding the substantially dried mixture in any suitable grinder;
(a4) sieving the ground, substantially dried particles and selecting a portion having a particle size of about 30-325 mesh, and (a5) mixing enough water with the particles obtained in step (a4) (in any suitable mixing device) to provide a shapable mixture contain mg about 5-40 (preferably about 8-30, more preferably about 8-15) weight-% water.
Shaping step (b) can be carried out in any conventional shaping equipment, such as an extruder equipped with a suitable die plate (through which the shapable mixture is extruded) or a tabletting machine (wherein the paste is compacted under pressure ) or a pelletizer (wherein the paste is agglomerized to ball-shaped particles). The particles obtained in step (b) can bave a cylindrical or a spherical or a trilobal or any other suitable shape. Presently preferred are cylindrical particles which can have any suitable size (preferably a ~099351 diameter of about 1/16-1/4 inch and a height of about 1/16-1/4 inch).
One preferred is a tabletting operation. The preferred processing aid which is present in the zirconia mixture during the tabletting process is zinc stearate (generally present in the zirconia mixture at a weight percentage of about 1 10 weight-%). When the shapable mixture is extruded, a cellulose gel and aqueous acetic acid are generally present in the mixture (generally at a level of about 0.5-5 weight-% cellulose and about 0.5-5 weight-% CH3CO2H).
Heating step (c) can be carried out in any suitable manner.
Generally, the shaped particles are first substantially dried (preferably in air at a temperature of about 100-280C for a time period of about 0.5-3 hours), and then calcined, preferably in air at a ~emperature of about 300-750C for a time period of about 1-5 hours.
The finished zirconia particles (preferably having a cylindrical shape, a diameter of about 1/16-1/4 inch and a height of about 1/1~-1/4 inch) preferably have a surface area ~measured by the BET/N2 method) of about 10-120 m2/g, a pore volume (measured by water intrusiGn at atmospheric pressure) of about 0.2-0.4 cc/g (more preferably about 0.25-0.35 cc/g), and an average crush strength (measured in accordance with ASTM method D4179-82, entitled "Standard Test Method for Single Pellet Crush Strength of Formed Catalyst Shapes") of about 5-30 lb. (more preferably about 20-25 lb.) per particle.
The following examples are presented to further illustrate this invention and are not to be construed as unduly limiting its scope.
Example I
This example ~llustrates the preparation of high strength zirconia tablets.
6 ~039351 In one test, 200 grams of RC-100 zirconia powder, marketed by Zirconia Sales of America, Atlanta, GA, having a particle size of about 1.0 micron, a BET/N2 surface area of about 94 m2/g and a pore volume of about 0.3 cc H70 per gram, was mixed in a Sigma mixer with about 140 mL
of a Nyacol~ colloidal zirconia solution in water (containing about 20 weight-% of colloidal zirconia particles and about 1.5 mole acetic acid per mole zirconia, marketed by PQ Corporation, Ashland, MA). The Nyacol~ colloidal zirconia solution was added in small aliquots over a time period of about 10 minutes with stirring. The mixture was then dried in a circulating air oven at 200C, ground and sieved.
To the portion of particles which were smaller than 30 mesh was added enough water to attain a water content of 11.04 weight-%.
Detailed Description of the Invention Zirconia powders which can be used in step (a) of the process of this invention are commercially available (e.g., from Zirconia Sales of America, Atlanta, GA). Preferably, the zirconia powder used in step (a) has a particle size of about 0.1-5 microns (more preferably about 0.5-1.2 microns), a pore volume (measured by water intrusion at atmospheric pressure) of about 0.2-0.5 cc/g (more preferably about 0.25-0.35 cc/g), and a BET/N2 surface area of about 25-150 m2/g (more preferably about 80-100 m2/g).
In step (a), the zirconia powder is mixed with either an aqueous colloidal solution of zirconia, preferably containing about 10-30 weight-70 of colloidal zirconia particles having a particle size of about 5-1000 (preferably about 5-200) nanometers, or alternatively, an aqueous mineral or carboxylic acid solution. Aqueous colloidal zirconia solutions are generally stabilized with acetic acid (preferred) or nitric acid and are commercially available (e.g., from PQ Corporation, Ashland, MA, under the product designation of Nyacol~). Non-limiting examples of suitable acids are H2S04, HN03, HCl, HC03H, CH3C02H, C2H5C02H, and higher carboxylic acids containing one or two carboxyl groups per molecule. Presently preferred are aqueous solution containing H2S04 or acetic acid, at a concentration of about 0.1 to 1.5 mol/l of the acid. Generally, the weight ratio of the colloidal zirconia solution or, alternatively, the aqueous acid solution to the zirconia powder is in the range of about 0.4:1 to about 1.5:1. Step (a) can be carried out in any suitable mixing device for a time period _ 4 2099351 sufficient to provide a substantially homogeneous mixture, generally for at least 1 minute (preferably about 5-20 minutes).
Step (a) is carried out so as to provide a shapable mixture containing about 5-40 (preferably about 8-30, more preferably about 8-15) weight-% H20. It is within the scope of this invention to carry out step (a) essentially in one step by adding enough water (either as part of the colloidal solutisn of zirconia or the aqueous acid solution, or in addition to these solutions) to provide the required water content. However, it is preferred to carry out step (a) as a series of substeps: (al) mixing powdered zirconia with an aqueous colloidal solution of zirconia or, alternatively, an aqueous solution of acetic or sulfuric acid, as described above; (a2) substantially drying the obtained wet mixture (preferably at a temperature of about 60-120C);
(a3) grinding the substantially dried mixture in any suitable grinder;
(a4) sieving the ground, substantially dried particles and selecting a portion having a particle size of about 30-325 mesh, and (a5) mixing enough water with the particles obtained in step (a4) (in any suitable mixing device) to provide a shapable mixture contain mg about 5-40 (preferably about 8-30, more preferably about 8-15) weight-% water.
Shaping step (b) can be carried out in any conventional shaping equipment, such as an extruder equipped with a suitable die plate (through which the shapable mixture is extruded) or a tabletting machine (wherein the paste is compacted under pressure ) or a pelletizer (wherein the paste is agglomerized to ball-shaped particles). The particles obtained in step (b) can bave a cylindrical or a spherical or a trilobal or any other suitable shape. Presently preferred are cylindrical particles which can have any suitable size (preferably a ~099351 diameter of about 1/16-1/4 inch and a height of about 1/16-1/4 inch).
One preferred is a tabletting operation. The preferred processing aid which is present in the zirconia mixture during the tabletting process is zinc stearate (generally present in the zirconia mixture at a weight percentage of about 1 10 weight-%). When the shapable mixture is extruded, a cellulose gel and aqueous acetic acid are generally present in the mixture (generally at a level of about 0.5-5 weight-% cellulose and about 0.5-5 weight-% CH3CO2H).
Heating step (c) can be carried out in any suitable manner.
Generally, the shaped particles are first substantially dried (preferably in air at a temperature of about 100-280C for a time period of about 0.5-3 hours), and then calcined, preferably in air at a ~emperature of about 300-750C for a time period of about 1-5 hours.
The finished zirconia particles (preferably having a cylindrical shape, a diameter of about 1/16-1/4 inch and a height of about 1/1~-1/4 inch) preferably have a surface area ~measured by the BET/N2 method) of about 10-120 m2/g, a pore volume (measured by water intrusiGn at atmospheric pressure) of about 0.2-0.4 cc/g (more preferably about 0.25-0.35 cc/g), and an average crush strength (measured in accordance with ASTM method D4179-82, entitled "Standard Test Method for Single Pellet Crush Strength of Formed Catalyst Shapes") of about 5-30 lb. (more preferably about 20-25 lb.) per particle.
The following examples are presented to further illustrate this invention and are not to be construed as unduly limiting its scope.
Example I
This example ~llustrates the preparation of high strength zirconia tablets.
6 ~039351 In one test, 200 grams of RC-100 zirconia powder, marketed by Zirconia Sales of America, Atlanta, GA, having a particle size of about 1.0 micron, a BET/N2 surface area of about 94 m2/g and a pore volume of about 0.3 cc H70 per gram, was mixed in a Sigma mixer with about 140 mL
of a Nyacol~ colloidal zirconia solution in water (containing about 20 weight-% of colloidal zirconia particles and about 1.5 mole acetic acid per mole zirconia, marketed by PQ Corporation, Ashland, MA). The Nyacol~ colloidal zirconia solution was added in small aliquots over a time period of about 10 minutes with stirring. The mixture was then dried in a circulating air oven at 200C, ground and sieved.
To the portion of particles which were smaller than 30 mesh was added enough water to attain a water content of 11.04 weight-%.
4 grams of zinc stearate was also added. This mixture was tabletted in a Stokes BB2 tabletting machine using 1/8" punches and 1/8" dies and employing 180 lb pressure. The tablets were dried in air for 1 hour at 250C in a furnace. Then the temperature of the furnace was increased to 550C over a period of 3 hours, and the dried particles were heated for 3 hours at 550C. The average crush strength of about 50 tested calcined tablets (measured in a crush strength apparatus equipped with two metal plates of 1/8 inch diameter and a 0-30 lb. force gauge) was 19 lb. The calcined tablets had a water intrusion pore volume of 0.27 cc/g, a BET/N2 surface area of 64 m2/g, and a packed bulk density of 1.47 g/cc.
In a second test, calcined zirconia particles were prepared substantially in accordance with the procedure of the first test, except that 140 mL aqueous sulfuric acid ~containing 2 volume-% H2SO4) was employed (in lieu of 140 mL of the colloidal Nyacol~ solution).
7 ~099351 Calcined zirconia particles had an average crush strength of 22 lb. per particle, a water intrusion pore volume of 0.26 cc/g, a BET/N2 surface area of 91 m2/g and a packed bulk density of 1.43 g/cc.
A more detailed porosity analysis of the calcined zirconia tablets by means of the mercury intrusion method, employing a Micromeritics (Norcross, GA) Autopore Hg PSD apparatus at a pressure ranging from 10 to 60,000 psi, revealed the following pore volume distribution (in cc/g):
First Test Second Test total pore volume 0.26 0.23 volume of pores < 50 A radius 0.08 0.14 volume of pores 50-300 ~ radius 0.16 0.08 volume of pores > 300 A radius 0.02 0.01 Example II
This example illustrates the preparation of zirconia particles by extrusion, in accordance with this invention.
100 grams of RC-100 zirconia powder (described in Example I), 2 grams of Avicel~ (a microcrystalline cellulose gel, provided by FMC
Corporation, Philadelphia, PA) and 20 mL of an aqueous, 2 volume-%
acetic acid solution were mixed in a Sigma mixer for 10 minutes.
Thereafter, an additional volume of 30 mL of the 2 volume-% acetic acid solution was added in small increments to give the paste -the consistency required for successful extrusion. The paste was extruded using an air-driven Bonnot laboratory extruder equipped with a copper die plate having four 1/8" diameter holes and 1/4" spacing between the die plate and the extruder barrel. The extrudates were dried overnight at about 8 ~09935~
200C in air. Thereafter, the particles were calcined as described in Example I.
The extrudates had an average crush strength of 6 lb. per particle, a water intrusion pore volume of 0.34 cc/g, a BET/N2 surface area of 60 m2/g. Mercury intrusion pore volume analysis of the calcined zirconia extrudates revealed:
total pore volume: 0.32 cc/g volume of pores ~ 50 A radius 0.02 cc/g volume of pores 50-300 A radius 0.22 cc/g volume of pores >300 A radius 0.08 cc/g.
The above test data show that the extrudates obtained in this example had a lower crush strength than the tablets prepared by the procedure of Example I, but the total pore volume of the extrudates was higher than that of the tablets described in Example I. A significant fraction of the pore volume of the extrudates was the volume of >300 A
pores (desirable for many catalytic reactions).
Reasonable variations, modifications and adaptations can be made within the scope of the disclosure and the appended claims without departing from the scope of this invention.
In a second test, calcined zirconia particles were prepared substantially in accordance with the procedure of the first test, except that 140 mL aqueous sulfuric acid ~containing 2 volume-% H2SO4) was employed (in lieu of 140 mL of the colloidal Nyacol~ solution).
7 ~099351 Calcined zirconia particles had an average crush strength of 22 lb. per particle, a water intrusion pore volume of 0.26 cc/g, a BET/N2 surface area of 91 m2/g and a packed bulk density of 1.43 g/cc.
A more detailed porosity analysis of the calcined zirconia tablets by means of the mercury intrusion method, employing a Micromeritics (Norcross, GA) Autopore Hg PSD apparatus at a pressure ranging from 10 to 60,000 psi, revealed the following pore volume distribution (in cc/g):
First Test Second Test total pore volume 0.26 0.23 volume of pores < 50 A radius 0.08 0.14 volume of pores 50-300 ~ radius 0.16 0.08 volume of pores > 300 A radius 0.02 0.01 Example II
This example illustrates the preparation of zirconia particles by extrusion, in accordance with this invention.
100 grams of RC-100 zirconia powder (described in Example I), 2 grams of Avicel~ (a microcrystalline cellulose gel, provided by FMC
Corporation, Philadelphia, PA) and 20 mL of an aqueous, 2 volume-%
acetic acid solution were mixed in a Sigma mixer for 10 minutes.
Thereafter, an additional volume of 30 mL of the 2 volume-% acetic acid solution was added in small increments to give the paste -the consistency required for successful extrusion. The paste was extruded using an air-driven Bonnot laboratory extruder equipped with a copper die plate having four 1/8" diameter holes and 1/4" spacing between the die plate and the extruder barrel. The extrudates were dried overnight at about 8 ~09935~
200C in air. Thereafter, the particles were calcined as described in Example I.
The extrudates had an average crush strength of 6 lb. per particle, a water intrusion pore volume of 0.34 cc/g, a BET/N2 surface area of 60 m2/g. Mercury intrusion pore volume analysis of the calcined zirconia extrudates revealed:
total pore volume: 0.32 cc/g volume of pores ~ 50 A radius 0.02 cc/g volume of pores 50-300 A radius 0.22 cc/g volume of pores >300 A radius 0.08 cc/g.
The above test data show that the extrudates obtained in this example had a lower crush strength than the tablets prepared by the procedure of Example I, but the total pore volume of the extrudates was higher than that of the tablets described in Example I. A significant fraction of the pore volume of the extrudates was the volume of >300 A
pores (desirable for many catalytic reactions).
Reasonable variations, modifications and adaptations can be made within the scope of the disclosure and the appended claims without departing from the scope of this invention.
Claims (20)
1. A process for preparing shaped zirconia particles comprising the steps of (a) mixing zirconia powder with an aqueous colloidal solution of zirconia, or, alternatively, an aqueous acid solution and adjusting the water content of the obtained mixture to a level of about 5 to about 40 weight-% H2O; (b) shaping the mixture obtained in step (a); and (c) heating the shaped particles obtained in step (b) at a temperature in excess of about 90°C.
2. A process in accordance with claim 1, wherein the zirconia powder employed in step (a) has a pore volume of about 0.2-0.5 cc/g, a surface area of about 20-150 m2/g and a particle size of about 0.1-5 microns.
3. A process in accordance with claim 2, wherein step (a) is carried out with an aqueous colloidal solution of zirconia containing about 10-30 weight-% colloidal zirconia particles having a particle size of about 5-1,000 nanometers.
4. A process in accordance with claim 3, wherein said aqueous colloidal solution of zirconia is stabilized with acetic acid or, alternatively, nitric acid.
5. A process in accordance with claim 3, wherein the weight ratio of said aqueous colloidal solution of zirconia to said zirconia powder is in the range of about 0.4:1 to about 1.5:1.
6. A process in accordance with claim 2, wherein step (a) is carried out with an aqueous acid solution containing at least one acid selected from the group consisting of H2SO4, HNO3, HC1, HCO2H, CH3CO2H
and C2H5CO2H.
and C2H5CO2H.
7. A process in accordance with claim 6, wherein said aqueous acid solution contains at least one acid is selected from the group consisting of sulfuric acid and acetic acid at an acid concentration of about 0.1-1.5 mole/l.
8. A process in accordance with claim 6, wherein the weight ratio of said aqueous acid solution to said zirconia powder is in the range of about 0.4:1 to about 1.5:1.
9. A process in accordance with claim 1, wherein step (a) is carried out for a time period of at least one minute, and wherein said water content is about 8-15 weight-% H2O.
10. A process in accordance with claim 1, wherein step (a) is carried out in five substeps:
(a1) mixing said zirconia powder with an aqueous colloidal solution of zirconia;
(a2) substantially drying the mixture obtained in step (a);
(a3) grinding the substantially dried mixture obtained in step (a2);
(a4) sieving the ground mixture obtained in step (a3) and selecting a portion having a particle size of about 30-325 mesh; and (a5) mixing water with the particles obtained in step (a4) to obtain a water content of about 8-40 weight-% H2O.
(a1) mixing said zirconia powder with an aqueous colloidal solution of zirconia;
(a2) substantially drying the mixture obtained in step (a);
(a3) grinding the substantially dried mixture obtained in step (a2);
(a4) sieving the ground mixture obtained in step (a3) and selecting a portion having a particle size of about 30-325 mesh; and (a5) mixing water with the particles obtained in step (a4) to obtain a water content of about 8-40 weight-% H2O.
11. A process in accordance with claim 10, wherein said zirconia powder has a pore volume of about 0.2-0.5 cc/g, a surface area of about 20-150 m/g and a particle size of about 0.1-5 microns; wherein said aqueous colloidal solution of zirconia contains about 10-30 weight-% colloidal zirconia particles having a particle size of about 5-1,000 nanometers; wherein the weight ratio of said aqueous colloidal solution of zirconia to said zirconia powder is in the range of about 0.4:1 to about 1.5:1, and wherein said water content attained in step (a5) is about 8-15 weight-% H2O.
12. A process in accordance with claim 1, wherein step (a) is carried out in five substeps:
(a1) mixing said zirconia powder with an aqueous solution of at least one acid selected from the group consisting of HC1, H2SO4, HNO3, HCO3H, CH3CO3H and C2H5CO3H;
(a2) substantially drying the mixture obtained in step (a1);
(a3) grinding the substantially dried mixture obtained in step (a2);
(a4) sieving the ground mixture obtained in step (a3) and selecting a portion having a particle size of about 30-325 mesh; and (a5) mixing water with the particles obtained in step (a4) to obtain a water content of about 8-40 weight-% H2O.
(a1) mixing said zirconia powder with an aqueous solution of at least one acid selected from the group consisting of HC1, H2SO4, HNO3, HCO3H, CH3CO3H and C2H5CO3H;
(a2) substantially drying the mixture obtained in step (a1);
(a3) grinding the substantially dried mixture obtained in step (a2);
(a4) sieving the ground mixture obtained in step (a3) and selecting a portion having a particle size of about 30-325 mesh; and (a5) mixing water with the particles obtained in step (a4) to obtain a water content of about 8-40 weight-% H2O.
13. A process in accordance with claim 12, wherein said zirconia powder has a pore volume of about 0.2-0.5 cc/g, a surface area of about 20-150 m/g and a particle size of about 0.1-5 microns; wherein said aqueous acid solution contains at least one acid selected from the group consisting of sulfuric acid and acetic acid at an acid concentration of about 0.1-1. 5 mole/l; wherein the weight ratio of said aqueous acid solution to said zirconia powder is in the range of about 0.4:1 to about 1.5:1; and wherein said water content attained in step (a5) is about 8-15 weight-% H2O.
14. A process in accordance with claim 1, wherein said shaping in step (b) is extrusion.
15. A process in accordance with claim 14, wherein step (b) is carried out in the presence of about 0.5-5 weight-% cellulose gel and about 0.5-5 weight-% acetic acid in said mixture.
16. A process in accordance with claim 1, wherein step (b) is tabletting.
17. A process in accordance with claim 16, wherein step (b) is carried out in the presence of about 1-10 weight-% zinc stearate in said mixture.
18. A process in accordance with claim 1, wherein heating step (c) is carried out in two substeps:
(c1) substantially drying said shaped particles at a temperature of about 100-280°C; and (c2) calcining the substantially dried particles obtained in step (c1) at a temperature of about 300-750°C.
(c1) substantially drying said shaped particles at a temperature of about 100-280°C; and (c2) calcining the substantially dried particles obtained in step (c1) at a temperature of about 300-750°C.
19. A process in accordance with claim 18, wherein step (c2) is carried out for a time period of about 1-5 hours.
20. A process in accordance with claim 1, wherein the shaped zirconia particles obtained in step (c) have a surface area of about 10-120 m2/g, a pore volume of about 0.2-4 cc/g and a crush strength of about 5-30 lb./particle.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/931,087 US5269990A (en) | 1992-08-17 | 1992-08-17 | Preparation of shaped zirconia particles |
| US07/931,087 | 1992-08-17 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2099351A1 CA2099351A1 (en) | 1994-02-18 |
| CA2099351C true CA2099351C (en) | 1997-04-08 |
Family
ID=25460210
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002099351A Expired - Fee Related CA2099351C (en) | 1992-08-17 | 1993-06-28 | Preparation of shaped zirconia particles |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US5269990A (en) |
| EP (1) | EP0585712B1 (en) |
| JP (1) | JPH06157038A (en) |
| AT (1) | ATE152432T1 (en) |
| CA (1) | CA2099351C (en) |
| DE (1) | DE69310289T2 (en) |
| DK (1) | DK0585712T3 (en) |
| ES (1) | ES2101177T3 (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5458834A (en) * | 1993-10-07 | 1995-10-17 | Corning Incorporated | Extrusion of low viscosity batch |
| US7157406B2 (en) * | 1994-12-17 | 2007-01-02 | Basf Aktiengesellschaft | Catalysts or carriers which consist essentially of monoclinic zirconium dioxide |
| DE4445142A1 (en) | 1994-12-17 | 1996-06-20 | Basf Ag | Catalysts or supports consisting essentially of monoclinic zirconia |
| EP0821620A1 (en) * | 1995-04-17 | 1998-02-04 | Engelhard Corporation | Formed compositions |
| US20040179994A1 (en) * | 2003-01-21 | 2004-09-16 | Fenouil Laurent Alain | Zirconia extrudates |
| JP5701474B2 (en) * | 2008-06-13 | 2015-04-15 | 富士フイルム株式会社 | Inorganic fine particle dispersion, organic-inorganic composite composition, molded article and optical component |
| KR102678205B1 (en) * | 2016-12-20 | 2024-06-24 | 쥐씨에이치 테크놀로지 코., 엘티디. | Particulate nucleating agents and methods for their preparation |
| WO2025090794A1 (en) | 2023-10-27 | 2025-05-01 | Johnson Matthey Public Limited Company | Zirconia support for heterogeneous catalysts |
Family Cites Families (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3311481A (en) * | 1962-03-01 | 1967-03-28 | Hitco | Refractory fibers and methods of making them |
| US3275580A (en) * | 1963-01-31 | 1966-09-27 | Fmc Corp | Shaped articles containing cellulose crystallite aggregates having an average level-off d.p. |
| US4485182A (en) * | 1982-07-28 | 1984-11-27 | Ibiden Kabushiki Kaisha | Powder composition for producing sintered ceramic |
| US4547487A (en) * | 1983-05-19 | 1985-10-15 | Gulf Research & Development Company | Process for preparing catalysts |
| JPS6042274A (en) * | 1983-08-11 | 1985-03-06 | 東芝セラミックス株式会社 | Manufacture of zirconia refractories |
| US4515904A (en) * | 1983-09-30 | 1985-05-07 | Standard Oil Company (Indiana) | Catalysts for the production of maleic anhydride by the oxidation of butane |
| JPS6115739A (en) * | 1984-04-25 | 1986-01-23 | Toa Nenryo Kogyo Kk | Hydrogenating-treatment catalyst |
| US4637995A (en) * | 1985-03-18 | 1987-01-20 | Corning Glass Works | Preparation of monolithic catalyst supports having an integrated high surface area phase |
| US4830994A (en) * | 1986-03-31 | 1989-05-16 | The Dow Chemical Company | Greenware binder |
| FR2598094B1 (en) * | 1986-04-30 | 1990-11-23 | Rhone Poulenc Chimie | ZIRCONIUM OXIDE CATALYST AND PROCESS FOR THE TREATMENT OF INDUSTRIAL WASTE GASES CONTAINING SULFUR COMPOUNDS |
| US4835126A (en) * | 1986-05-06 | 1989-05-30 | Exxon Research & Engineering Company | Process for preparing a catalyst for the preparation of a carboxylic anhydride |
| JPS6311572A (en) * | 1986-07-02 | 1988-01-19 | 日本鋼管株式会社 | Method for purifying non-oxide ceramic powder |
| US4937212A (en) * | 1988-12-19 | 1990-06-26 | Minnesota Mining And Manufacturing Company | Zirconium oxide fibers and process for their preparation |
| GB9108656D0 (en) * | 1991-04-23 | 1991-06-12 | Shell Int Research | Process for the preparation of a catalyst or catalyst precursor |
-
1992
- 1992-08-17 US US07/931,087 patent/US5269990A/en not_active Expired - Fee Related
-
1993
- 1993-06-28 CA CA002099351A patent/CA2099351C/en not_active Expired - Fee Related
- 1993-08-16 DK DK93113112.2T patent/DK0585712T3/en active
- 1993-08-16 JP JP5202159A patent/JPH06157038A/en active Pending
- 1993-08-16 EP EP93113112A patent/EP0585712B1/en not_active Expired - Lifetime
- 1993-08-16 ES ES93113112T patent/ES2101177T3/en not_active Expired - Lifetime
- 1993-08-16 DE DE69310289T patent/DE69310289T2/en not_active Expired - Fee Related
- 1993-08-16 AT AT93113112T patent/ATE152432T1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| DE69310289T2 (en) | 1997-08-14 |
| EP0585712A1 (en) | 1994-03-09 |
| JPH06157038A (en) | 1994-06-03 |
| DE69310289D1 (en) | 1997-06-05 |
| DK0585712T3 (en) | 1997-10-27 |
| ATE152432T1 (en) | 1997-05-15 |
| US5269990A (en) | 1993-12-14 |
| ES2101177T3 (en) | 1997-07-01 |
| EP0585712B1 (en) | 1997-05-02 |
| CA2099351A1 (en) | 1994-02-18 |
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